@inproceedings{heitlager2007practical,
  title={A practical model for measuring maintainability},
  author={Heitlager, I. and Kuipers, T. and Visser, J.},
  booktitle={Quality of Information and Communications Technology, 2007. QUATIC 2007. 6th International Conference on the},
  pages={30--39},
  year={2007},
  organization={IEEE}
}

@book{mcconnell2009code,
  title={Code complete},
  author={McConnell, S.},
  year={2009},
  publisher={O'Reilly Media, Inc.}
}

@article{gill1991cyclomatic,
  title={Cyclomatic complexity density and software maintenance productivity},
  author={Gill, G.K. and Kemerer, C.F.},
  journal={Software Engineering, IEEE Transactions on},
  volume={17},
  number={12},
  pages={1284--1288},
  year={1991},
  publisher={IEEE}
}